← 14 15 16 →
Cardinalfifteen
Ordinal15th
(fifteenth)
Factorization3 × 5
Divisors1, 3, 5, 15
Greek numeralΙΕ´
Roman numeralXV
Binary11112
Ternary1203
Senary236
Octal178
Duodecimal1312
Hebrewט"ו (Tet Vav)

15 (fifteen) is the natural number following 14 and preceding 16.

## Mathematics

15 is:

Furthermore,

2, 3, 5, 7, 23, 37, 53, 73, 313, 317, 373, 797, 3137, 3797, 739397 (sequence A020994 in the OEIS)

## Religion

### Sunnism

The Hanbali Sunni madhab states that the age of fifteen of a solar or lunar calendar is when one's taklif (obligation or responsibility) begins and is the stage whereby one has his deeds recorded.[9]

## References

1. ^ Sloane, N. J. A. (ed.). "Sequence A001358 (Semiprimes (or biprimes): products of two primes.)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
2. ^ Sloane, N. J. A. (ed.). "Sequence A001748 (a(n) = 3 * prime(n))". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
3. ^ Sloane, N. J. A. (ed.). "Sequence A000110 (Bell or exponential numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
4. ^
5. ^ Sloane, N. J. A. (ed.). "Sequence A000384 (Hexagonal numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
6. ^ Sloane, N. J. A. (ed.). "Sequence A051867 (pentadecagonal numbers.)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
7. ^
8. ^ H.S.M. Coxeter (1954). "Regular Honeycombs in Hyperbolic Space". Proceedings of the International Congress of Mathematicians. 3: 155–169. CiteSeerX 10.1.1.361.251.
9. ^ Spevack, Aaron (2011). Ghazali on the Principles of Islamic Spiritualit. p. 50.